Gentlemen,

I have a Heym Express in .500 A-Square.
Like the colleagues wrote, it is the .460 Weatherby enlarged for .510 bullets.

A-Square ammunition is advertised as 600grs bullets @ 2470fps.
My rifle weighs 4,6 kg and has no muzzle brake, so some kind of humor is needed to fire more shots with "standard" ammunition.

best regards
Rolf